Concrete occupies unique position among the modern construction materials, Concrete is a material used in building construction, consisting of a hard, chemically inert particulate substance, known as an aggregate (usually made for different types of sand and gravel), that is bond by cement and water. Pozzolonas are Supplementary cementitious materials (SCMs) used to partially replace cement in concrete. They are often added to mortar to make the mixtures more economical, reduce permeability, increase strength and increase durability. The use of supplementary cementitious materials in concrete is advantageous in many ways. Their use improves and increases rheological properties, the strength of concrete and the resistance to sulphate attack.